Where are the dlc files?

Hey guys, I am looking for hard copy's of the dlc files to back them up (I play 4.2.2 on steam) but one or two of them say I don't own them anymore and now I am worried about the others. Doubt anyone has a copy of the 4.2.2 chorfs or any pre 5.0 dlc but please hmu if you do or if you know where these files are located so I can keep my version old thanks!